In general when a color photographic image is produced, after giving an exposure to a silver halide light-sensitive color photographic material, the color photographic material undergoes color development. Then, in the exposed area, oxidized aromatic primary amine color developing agent reacts with a dye-forming coupler, to generate a dye and thus a color image is formed. In this photographic process, color reproduction method using subtractive color system is used, and thereby a color image consisting of yellow, magenta, and cyan dye images is formed.
Heretofore, as the photographic coupler used to form a yellow dye image, for example, acyl acetanilide-type coupler is known. As the coupler for forming a magenta dye image, for instance, pyrazolone, pyrazolobenzimidazole, pyrazolo triazole and indazolone-type couplers are known. And as for the coupler for forming a cyan dye image, phenol or naphthol type coupler is usually used. It is desirable that the dye image obtained from these couplers is not changed or discolored easily, even when it is exposed to light for a long time, or when it is stored under high temperature and high humidity.
However, up to now, in spite of the fact that various researches and developments have been made, the above-mentioned phenol type coupler and naphthol type couplers are still insufficient in view of spectral absorption characteristics and durability against heat and moisture. Various attempts and proposals, aiming at improving these points, including in search of a substituent in the coupler have been made, however, a coupler, which satisfies all these requirements has not been found yet.
A photographic coupler, by which a dye image having excellent spectral absorption characteristics and improved durability against heat and moisture can be obtained, is desired.